Nigel 'Numbuh 1' Uno / Hoagie Pennywhistle 'Numbuh 2' Gilligan Jr / Numbuh 101 (voice)

Ben Diskin

Acting

Kuki 'Numbuh 3' Sanban (voice)

Lauren Tom

Acting

Wally 'Numbuh 4' Beatles / Mr. Fibb / Toilenator / Joaquin / Tommy Gilligan (voice)

Dee Bradley Baker

Acting

Abigail 'Numbuh 5' Lincoln / Former Numbuh 11 - Cree Lincoln (voice)

Cree Summer

Acting

Chad Dickson (voice)

Jason Harris

Acting

Crazy Old Cat Lady/Gramma Stuffum (voice)

Grey DeLisle

Acting

Mr. Boss / Mr. Fizz / Benedict Wigglestein (voice)

Jeff Bennett

Acting

Fanny 'Numbuh 86' Fulbright / Computer (voice)

Jennifer Hale

Acting

Stickybeard (voice)

Mark Hamill

Acting

Knightbrace / Mr. Wink (voice)

Tom Kenny

Acting

Father (voice)

Maurice LaMarche

Acting

Patton 'Numbuh 60' Drilovsky (voice)

Matt Levin

Acting

Monty Uno (voice)

Frank Welker

Acting

Grandfather (voice)

Neil Ross

Acting

Count Spankulot (voice)

Daran Norris

Acting

Rachael T. 'Numbuh 362' McKenzie (voice)

Rachael MacFarlane

Acting

Sector Z Numbuh 0.1 - Bruce (voice)

Ogie Banks

Acting

Sonya - Number 83 / Lee - Numbuh 84 (voice)

Janice Kawaye

Acting

Numbuh Zero / Lenny - Sector Z Numbuh 0.4 (voice)

Dave Wittenberg

Acting

Additional Voices (voice)

Cam Clarke

Acting

Additional Voices (voice)

Candi Milo

Acting